Captive screws or captive fasteners are typically designed for permanent hold or captivation within a target assembly or housing, including upon servicing. They can provide a secure joining, and avoid fastener loss or damage that might be caused by a loose part. Typical captive screws may be made with thread locking, press-fitting, or broaching to accomplish an anchor-hold within a larger assembly housing. A captive fastener may also be fused with the material into which it is joined, either through cold forming or welding.
Typical captive fasteners are captured by a first body and engage with a second body. U.S. Patent Application No. 20150223847 discloses a fixation screw for implantation in a body comprising different fastening mechanisms. Typical captive fasteners are limited in that they are not removeably attached to a first body and provide releasable fixation with respect to a second body.
In certain mechanical configurations, it may be desirable to have a captive fastener which may be permanently attached and removeably attached to a first member while engaging with a second member. It may be desirable to have a captive fastener which can act as a set screw with respect to a second member in addition to captively fastening to a first member. It may be desirable to have a captive fastener which has a flexible or rigid barb member for causing permanent attachment and a threaded portion for causing removable attachment to the first member. It may be desirable to have a captive screw which allows for longitudinal and rotational motion between a first member and a second member and is capable of locking the first member with respect to the second member.
The device of the present invention overcomes limitations of the prior art in that a captive screw is provided which is capable of repeatedly and easily being driven in and out between a first surface and a second surface of a channel in a first member to adjust longitudinal and rotation position of a first member with respect to a second member, and is prevented from fully disengaging from the first member during repositioning of the first member with respect to the second member.